Manufacture of incandescent lamps



H. (:7.v ANDERSON IANUFAGTURE 0F. INQANDESCENT LAMPS Filed April 29.1922 FIGQ "INVENTOR HOMER G. ANDERSQ-N ATTORNEY Patented May 3, 1927.

'E Q ATENTN M CE HOMER GEORGE ANDERSON, OF EAST o ANGE, NEW EEsEv,AssmNo To wEs'rING- HOUSE LAMP COMPANY, A coEro'EA'rIoN or rEN sYLvANIA,

MANUFACTURE OF INCANIDESCENT LAMPS. I

Application filed April 29, 1922. j Serial No. 557,371.

r This invention relates to the manufacture of incandescent lamps andhas special refer ence to a device for applying and indicating thetension on a lamp filament which is being formed.

7 An ob 'ect of my invention is to provide a device for indicating, atall times,- the tension on a filament being threaded to afila'ment-forming machine. Another object of my invention is to providean'indicator whereby thetension on a filament being fed into a formingmachine can be determined, so that a substantially uniform tension maybe applied thereto, whereby more desirable results will be secured inthe manufacture of filaments which are bent into zigzag form. y I 'Afurther object, of my invention is to provide a device for indicatingfilamenttension in a filament-forming machine and a tensioning device toprovide for accurately adjusting such tension so that filaments ofdifferent gauge may be formed. a

A still further object of my invention is the manufacture of filamentsbent into zigzag form, while maintaining uniform the.

cross-section thereof. p

, Other objects and advantages of the invention will be apparent as thedescription proceeds.

- In bending filaments preparatory to winding the same upon spiders forincandescent lamps, it has been customary to feed the filament into themachine under a tension more'or less indefinite and with no provisionfor indicating under what tension the fil'a-r ment is formed. It isfound that unsatis-' factory results, such as non-uniform cross sectionand short burn-out life of the formed filament, have been due to thenon-uniform tension to'which the filament has been subjected while beingbent into shape and heated in an atmosphere of forming gas. According tomy invention, I propose to form the filament while subjected to asubstantially uniform tension, which is' adjustable according to the size ofand properties desired for the filament and which is indicatedpreferably by the movement of a pointer over a graduated scale.

It has been found that the homogeneity, amount of stretching, molecularstructure and the burn-out life of a filament are dependent on theforming tension, that is, the higher the forming tension, the shorterthe tachment and tensioning devicefor' a fila ture. The controllingtension appears to be the maximum tension to whichlthe particularsection of filament considered, is subected while beingformed.',fA.filament subjected to a uniform tension according to my'invention,m'ay be formed at a higher tension than the average tensionon a filament viously "used, for thesamereduction in burn-out life;v Byaccurately controlling the "tension at which a filament 'is formed, Ican therefore control theproperties thereof, such as' the burn-out life,molecular structure, 'homogenelty and amount ment-bending orformingmachine; Q

Fig. 2 1s a side 'view of 'the dev ce shown inFlg. 1, the filament andtensloning device therefor being omitted for clearness; I

Fig. 3is'a section on the line IIIIIi of life, which depends on themolecular strucformed under 'a' varying tension as 'pre Fig. 1 lookingin the direction of the arrows, the set screw being omitted forclearness;

and,

Fig. 4: is a side view of a filament-forming machine illustrating anapplication of my invention thereto.

My invention may be employed in connection with an apparatus forbending' filamentssuch'as is described and claimedin J the applicationof Anton Lederer, Serial Number 879,761, filedDeceinber 30, 1914,

now Patent #1,4t19,153, June 13, 1922,'and assigned to the,l/Vestinghouse Lamp Com pany, or it may be usedon the modificationthereof shown in Fig. 4.

In said figure, a frame 1 in the form of a table carries the variousparts of themachine, Beneath the top' of this frame may be mounted adrivingmechanism including a driving shaft 2 connected through gearing 3to the lower end of avcounter shaft 4 mounted in a standard 5 on the topof the frame. The counter shaft 4 may be geared at its upper, end to ahorizontal shaft6 suitably journaled on the standard 5 andcarry anadjustable drum 7 over which the" filament 8 to'be formed is wound bythe movement of-the drum. The filament wireis 'given a sinuous orzigzagform by being wound back and forth on suitable forming the collar35' supporting the spring, reduces the-lever arm -of thefilamentpassin'giover the pulley 32 and thereby provides, in effect,

a. stiffer spring for being stressed I by the I filament. f

When aspring is desired that lessstifi', I one of the other studs, forinstance 'stu d' l5,

is used, as shown in 1, thereby increasing the lever arm of the filamentfor lndicating a weaker tension for the same displace- .ment of thespring. In this way, therange of tensions indicated on the scale maybevaried to suit the filament being formed.

The fiat leaf spring may be calibrated by detaching the arm'lO from themachine and supporting it in horizontal position. The

spring is then loaded by means of a thread or wire passing thereover andplaced under 1, the dot-dash position of the pointer shows a positionthereof when the filament is under tension.

By my invention, I have provided means whereby the filament tension maybe accurately controlled and measured. The provision of the tensioningdevice for a separate drum instead ofdirectly for the filament spool, asheretofore, eliminates the former objectionable features of eccentricspools,

spools of various diameters and in various stages of being unwound andnon-uniform axle-spoo1 spring-grips. These former objectionable featuresmade it lmposslble to keep the filament under a uniform tension.

fill By eliminating the noted former defects, I Y

can wind the filament on a continuous forming machine under. a uniformtension, which may be accurately adjusted to any deslred degree by myexternal tension control and shown by my indicator and thereby produce ahomogeneous filament of unvarying crosssection, stretched in the formingmachine according to the tension applied thereto, be cause it .is heatedin the forming machine while under a uniform tension. The forming of thefilament under a uniform tension, makes it possible to form filaments ofmuch smaller cross-sections than heretofore, because breakage due tofluctuations in tension is eliminated. J

lVhile I havev illustrated what I now consider to be a preferredembodiment of my invention, it is to be understood that many changes maybe effected therein and I wish to be limited only by the scope of theappended claims.

What is claimed is:

1. In a filament-bending machine, a filament-threading arm, a scaleattached thereto, a resilient plate attached to said arm, said plate 1means "for guiding the, filament' and a po nter'movable along'the scaleto indicate the tension on the"filament."

2.,In a filamentebending machinefla filamentthreading' 'arm,i agraduatedscale I atl tached thereto, a resilient plate attached to acollar adjustable on said arm, said plate carrying means for guiding thefilament and v a pointer-f movable along'the 'scalei'to indicate'thetension on'the'filament. I

. 3. A forming machine comprising a filament-threading rm, means forindicating the tension on thefilam'ent bein'g formed comprising a giaduat'ed scale attached to the filament threadingarm, a flat springcarrying a pulley for guiding-the filament and a pointer adapted to moveover the scale.

4. In a'filament-bending machineyan arm holding 'me'ans" for guidingafilament and movable for the purpose of bending the filament, means forindicating the tension on the filament being bent comprising a resilientmember, a pulley carried on sald member over which the filament passesand a pointer adapted to indicate filament tension.

5. In a filament-forming machine, a filament threading arm, a graduatedscale attached thereto, means for indicating filament tension comprisinga spring member adjustably held on said arm and holding a pulley u overwhich the filament passes and a pointer attached to said spring andindicating the tension on the filament, by its position with respect tothe scale.

' 6. In a filament-forming machine, an'arm for guiding the filament, agraduated scale attached thereto, a collar clamped on said arm andholding a resilient member and a bushing for modifying the effectivestiffness of the resilient member comprising a hollow cylindrical memberon said arm provided with studs of various lengths adapted to engage theresilient member, said resilient member supporting means for guiding thep filament and a pointer moving over the graduated scale. v V

7. Means .for indicating the tension on a filament being Woundupon afilament-forming machine comprising a threading arm, a scale and aspring 011 said arm, said spring carrying a filament guiding pulley anda pointer movable over said scale.

8. Means for indicatlng the tension on a filament being wound upon afilament-forming machine comprising a threading arm, ,a scale and aspring on said arm, said spring carrying a filament guiding pulley and apointer movable over said scale, a bushing adjustably held on said armand provided with studs projecting various distances from r the same andeach adapted to engage the spring according to the positionof the bush-9. Means for indicating the tension on a filament belng wound uponafilament-form- ,ing machine comprising atthreading arm, ,a

;.graduated scale supported near the free end of saidcarm, a clampingmember adjustably holding aspring on said arm, said spring ea rrying :afilament guiding pulley and a pointer movable over said scale, a bushingadjustably held on said arm and provided .WithYStlIdS projecting variousdistances from c the same andeach adapted tolbe engaged with the springaccording to, the position of the bushing. I

- 1 0. A filament-bendingmachine comprising ,a forming drum, a cylinder,a filament 7 cylinder, a resilient member having a pulley over which thefilament passes and means associated with said member for indlcatingsubscribed my the tension .on the filament as the filament passes ontothe forming drum. I

11. lnafi-lamentbending machine, a spool from which the filament isunwound, an accurately formed, and centered drum around which thefilament, is drawn without sliping, a braking device on the drum,adjustable so that any desired tension may be applied to the filament, aresilient member holding an idler over which the filament passes in sucha way that bending occurs if the filament tension varies and 'means forindicating the tension on the filament as it is about to ,be bent.

In testimony whereof, I have hereunto HOMER GEORGE ANDERSON.

name this 28th day of April,

